<i>J Street and their ilk do not fear generally fear antisemitism (I suspect that many Jews on campuses who publicly espouse anti-Israel positions do so out of fear). They are ideologically opposed to any form of nationalism.</i>
If J Street’s issue was nationalism then they wouldn’t be pro Palestinian either because the Palestinians are way more nationalistic than the Israelis are.
Their issues are that they very much want to assimilate completely but (1) it is difficult for them to be pro-Israel when the prevailing feeling in the left is so anti-Israel (2)anti-Semitism masked as anti-Israel makes them realize it isn’t so easy to assimilate .
To drown out those thoughts they take a very anti-Israel position to tell themselves there is no anti-Semitism in the anti Israel bias and to tell the non-Jews. “No we’re not like those Jews. We are just like you . Let us assimilate among you.
It isn’t for no reason that the head of J Street frequently takes a salami-ham-and-cheese sandwich to interviews. He is trying to make a point that he has nothing to do with “Jewish” Jews.